Relief valve



-'March 20, 1934. I K, s. M. DAVIDSCN 1,951,926

v RELIEF VALVE Filed July 1a, 1929 Inumr 715-7151986- K991112751. I

(M MAW M Patented Mar. 20, 1934 UNITED STATES PATENT OFFICE RELIEF VALVEsetts Application July 13, 1929, Serial No. 377,968

2 Claims.

The present invention relates to valves for automatically relievingthe.pressure within portable containers, such as containers employed forconveying liquefied petroleum gas.

it is desirable to provide in connection with such containers some formof relief which will prevent bursting of the container under abnormalpressure. Such a pressure may well result from the temporary andabnormal heating of the container, either during transportation or use.These containers have been provided with frangible seals designed torupture under such pressure, and avoid bursting of the tank. However,devices of this character are relatively unsatisfactory due to the factthat rupture of the seal causes the contents of the tank to becomeempty, and may in addition cause the liberation of large quantities of acombustible or explosive medium when mixed with air.

The purpose of the present invention is to provide a simple andeiiicient device for relieving abnormal pressures in containers of thischaracter which vents only a sufiicient amount of gas to relieve thepressure, and thereafter closes tightly and automatically to preventescape of the bulk of the contents. The device may be readily insertedwithin a container, and when installed does not project therefrom in amanner to become easily broken or interfere with the convenient handlingof the container.

The various features of the invention consist in certain novelconstructions, combinations and arrangements of parts hereinafterdescribed and claimed, the advantages of which will be obvious to thoseskilled in the art from the following description.

The accompanying drawing, illustrating the preferred form of theinvention, is a sectional elevation of the improved device embodied in acontainer of the usual type.

As indicated in the drawing, the container 10, which may be providedwith a boss 12, has threaded thereinto a valve body 14 having anexternal threaded portion which projects well within the container whenmounted in position. The inner portion of the valve body is providedwith a guide 16 for a valve stem 18, having a head 20 which ispositioned within a chamber 22 formed within the' threaded portion ofthe valve body as indicated. The chamber has. communication with theinterior of the container through an axial port 24 in free communicationwith transverse ports 26. The port 24 is normally closed by the valve-20 which is maintained on its seat by a spring 28 surrounding the innerend of the valve stem and interposed between abutments 30 and 32. Theabutment 30 is supported on the inner end of the guide member 16, andthe cooperating abutment 32 is supported on an adjustable head 34threadedly connected with the valve stem at 36 and maintained inadjusted position by a lock nut 38. Located beyond the valve 20 andnormally hermetically sealing the chamber 22 is a frangible copperdisk40 which is clamped within the valve body by a plug 44 which engages thefrangible disk through interposed aluminum packing ring 46. In thenormal condition of the device the contents of the container arehermetically sealed from the atmosphere through the frangible disk.However, the creation of an abnormal pressure within the container issufficient to elevate the valve 20 and rupture the frangible disk,relieving the pressure. Venting a portion of the contents withconsequent relief of pressure causes the valve 20 to be reseated,preventing further escape of contents from the container. In ordinarypractice the 'valve 20 will be set to relieve at a lower pressure thanthe rupturing pressure of the disk.

With this type of construction the major portion of the valve and theoperating mechanism are located within the container, the onlyprojecting portion being the head of the valve body and the sealingplug. Furthermore, a ruptured disk may be replaced by removal of theplug without dismounting the valve from the container. When the deviceis in Working condition the valve and cooperating parts are sealed fromdust and dirt by the frangible disk, and no opportunity is present forengagement of foreign material between the valve and seat or within themoving parts of the valve.

What is claimed is:

1. A relief valve for portable containers comprising a body portionadapted to be mounted in the container and having, a chamber and apassage affording communication between the inner end of the chamber andinterior of the container, a spring-pressed valve normally closing thepassage at the inner end of the chamber and wholly contained within thecontainer, a frangible member detachably supported within the body atthe outer end of the chamber, and a holding plug mounted within theouter end of the body and detachably retaining the frangible member inplace, the plug being removable and the frangible member replaceablewithout dismantling the body from the container.

2. A relief valve for portable containers comprising an externallythreaded body portion screwed into the container and her extending intothe threaded a passage afiording the container, an outd valve mountedthe chamber and arranged y within the container for sealing againstingress of air through the passage at the inner end of the chamber, anda frangible member hermetically sealing the outer,

end of the chamber beyond the valve and preventing access to the valveand seat and the chamber sealed by the frangible member.

KENNETH S. M. DAVIDSON.

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